Count the running time and actual IO processing time of the sqpoll
thread, and output the statistical data to fdinfo.
Variable description:
"work_time" in the code represents the sum of the jiffies of the sq
thread actually processing IO, that is, how many milliseconds it
actually takes to process IO. "total_time" represents the total time
that the sq thread has elapsed from the beginning of the loop to the
current time point, that is, how many milliseconds it has spent in
total.
The test tool is fio, and its parameters are as follows:
[global]
ioengine=io_uring
direct=1
group_reporting
bs=128k
norandommap=1
randrepeat=0
refill_buffers
ramp_time=30s
time_based
runtime=1m
clocksource=clock_gettime
overwrite=1
log_avg_msec=1000
numjobs=1
[disk0]
filename=/dev/nvme0n1
rw=read
iodepth=16
hipri
sqthread_poll=1
The test results are as follows:
Every 2.0s: cat /proc/9230/fdinfo/6 | grep -E Sq
SqMask: 0x3
SqHead: 3197153
SqTail: 3197153
CachedSqHead: 3197153
SqThread: 9231
SqThreadCpu: 11
SqTotalTime: 18099614
SqWorkTime: 16748316
The test results corresponding to different iodepths are as follows:
|-----------|-------|-------|-------|------|-------|
| iodepth | 1 | 4 | 8 | 16 | 64 |
|-----------|-------|-------|-------|------|-------|
|utilization| 2.9% | 8.8% | 10.9% | 92.9%| 84.4% |
|-----------|-------|-------|-------|------|-------|
| idle | 97.1% | 91.2% | 89.1% | 7.1% | 15.6% |
|-----------|-------|-------|-------|------|-------|
Signed-off-by: Xiaobing Li <[email protected]>
---
changes：
v10:
- Resubmission based on for - 6.9 / io_uring
v9:
- Modified the encoding format
v8:
- Get the work time of the sqpoll thread through getrusage
v7:
- Get the total time of the sqpoll thread through getrusage
- The working time of the sqpoll thread is obtained through ktime_get()
v6:
- Replace the percentages in the fdinfo output with the actual running
time and the time actually processing IO
v5：
- list the changes in each iteration.
v4：
- Resubmit the patch based on removing sq->lock
v3：
- output actual working time as a percentage of total time
- detailed description of the meaning of each variable
- added test results
v2：
- output the total statistical time and work time to fdinfo
v1：
- initial version
- Statistics of total time and work time
io_uring/fdinfo.c | 7 +++++++
io_uring/sqpoll.c | 17 ++++++++++++++++-
io_uring/sqpoll.h | 1 +
3 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/io_uring/fdinfo.c b/io_uring/fdinfo.c
index 976e9500f651..37afc5bac279 100644
--- a/io_uring/fdinfo.c
+++ b/io_uring/fdinfo.c
@@ -55,6 +55,7 @@ __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *f)
struct io_ring_ctx *ctx = f->private_data;
struct io_overflow_cqe *ocqe;
struct io_rings *r = ctx->rings;
+ struct rusage sq_usage;
unsigned int sq_mask = ctx->sq_entries - 1, cq_mask = ctx->cq_entries - 1;
unsigned int sq_head = READ_ONCE(r->sq.head);
unsigned int sq_tail = READ_ONCE(r->sq.tail);
@@ -64,6 +65,7 @@ __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *f)
unsigned int sq_shift = 0;
unsigned int sq_entries, cq_entries;
int sq_pid = -1, sq_cpu = -1;
+ u64 sq_total_time = 0, sq_work_time = 0;
bool has_lock;
unsigned int i;
@@ -147,10 +149,15 @@ __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *f)
sq_pid = sq->task_pid;
sq_cpu = sq->sq_cpu;
+ getrusage(sq->thread, RUSAGE_SELF, &sq_usage);
+ sq_total_time = sq_usage.ru_stime.tv_sec * 1000000 + sq_usage.ru_stime.tv_usec;
+ sq_work_time = sq->work_time;
}
seq_printf(m, "SqThread:\t%d\n", sq_pid);
seq_printf(m, "SqThreadCpu:\t%d\n", sq_cpu);
+ seq_printf(m, "SqTotalTime:\t%llu\n", sq_total_time);
+ seq_printf(m, "SqWorkTime:\t%llu\n", sq_work_time);
seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files);
for (i = 0; has_lock && i < ctx->nr_user_files; i++) {
struct file *f = io_file_from_index(&ctx->file_table, i);
diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c
index 82672eaaee81..363052b4ea76 100644
--- a/io_uring/sqpoll.c
+++ b/io_uring/sqpoll.c
@@ -253,11 +253,23 @@ static bool io_sq_tw_pending(struct llist_node *retry_list)
return retry_list || !llist_empty(&tctx->task_list);
}
+static void io_sq_update_worktime(struct io_sq_data *sqd, struct rusage *start)
+{
+ struct rusage end;
+
+ getrusage(current, RUSAGE_SELF, &end);
+ end.ru_stime.tv_sec -= start->ru_stime.tv_sec;
+ end.ru_stime.tv_usec -= start->ru_stime.tv_usec;
+
+ sqd->work_time += end.ru_stime.tv_usec + end.ru_stime.tv_sec * 1000000;
+}
+
static int io_sq_thread(void *data)
{
struct llist_node *retry_list = NULL;
struct io_sq_data *sqd = data;
struct io_ring_ctx *ctx;
+ struct rusage start;
unsigned long timeout = 0;
char buf[TASK_COMM_LEN];
DEFINE_WAIT(wait);
@@ -286,6 +298,7 @@ static int io_sq_thread(void *data)
}
cap_entries = !list_is_singular(&sqd->ctx_list);
+ getrusage(current, RUSAGE_SELF, &start);
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
int ret = __io_sq_thread(ctx, cap_entries);
@@ -296,8 +309,10 @@ static int io_sq_thread(void *data)
sqt_spin = true;
if (sqt_spin || !time_after(jiffies, timeout)) {
- if (sqt_spin)
+ if (sqt_spin) {
+ io_sq_update_worktime(sqd, &start);
timeout = jiffies + sqd->sq_thread_idle;
+ }
if (unlikely(need_resched())) {
mutex_unlock(&sqd->lock);
cond_resched();
diff --git a/io_uring/sqpoll.h b/io_uring/sqpoll.h
index 8df37e8c9149..4171666b1cf4 100644
--- a/io_uring/sqpoll.h
+++ b/io_uring/sqpoll.h
@@ -16,6 +16,7 @@ struct io_sq_data {
pid_t task_pid;
pid_t task_tgid;
+ u64 work_time;
unsigned long state;
struct completion exited;
};
--
2.34.1
On Wed, 28 Feb 2024 17:12:51 +0800, Xiaobing Li wrote:
> Count the running time and actual IO processing time of the sqpoll
> thread, and output the statistical data to fdinfo.
>
> Variable description:
> "work_time" in the code represents the sum of the jiffies of the sq
> thread actually processing IO, that is, how many milliseconds it
> actually takes to process IO. "total_time" represents the total time
> that the sq thread has elapsed from the beginning of the loop to the
> current time point, that is, how many milliseconds it has spent in
> total.
>
> [...]
Applied, thanks!
[1/1] io_uring: Statistics of the true utilization of sq threads.
commit: 4c73fd7498f75e06462e94b907e9cc79e0726e0c
Best regards,
--
Jens Axboe